The present invention relates to a method for controlling the speed of an internal combustion engine and a closed-loop speed control system for carrying out the method.
The speed of an internal combustion engine, which refers to the frequency of the rotation of the internal combustion engine per unit of time, is generally controlled during operation, in particular held constant during certain periods of time. For this purpose, a speed controller is used, which influences the operation of the internal combustion engine by presetting a correcting variable in such a way that the speed is preferably held constant at the predefined level which corresponds to a set speed, wherein disturbances are reduced. Different kinds of controllers are known, whose behavior is determined via controller parameters and may be influenced via their selection.
The publication DE 10 2004 023 993 A1 describes a method for controlling the speed of an internal combustion engine generator unit with a clutch during the starting process. In this method, after the startup of the first run-up ramp, when it is detected that the clutch has engaged, a switch is made from a first parameter set to a second parameter set, whereupon the first parameter set is deactivated. In the second parameter set, a second run-up ramp is set, which determines the presetting of the set speed.
In the described method, controller parameters are thus switched as a function of a clutching signal. This clutching signal must be available as an external signal. The correcting variable of the described speed controller is the fuel injection quantity. Thus, a use in systems with multiple fuels is not readily possible.